1. Field of the Invention
This invention relates to electrical switching apparatus, especially such as power circuit breakers, network protectors and switches, used in electric power distribution circuits carrying large currents. More particularly, it relates to such apparatus having a disengageable handle for the ratchet mechanism which charges the large spring used to close the switching apparatus.
2. Background Information
Electrical switching apparatus for opening and closing electric power circuits typically utilize an energy storage device in the form of one or more large springs to close the contacts of the device into the large currents which can be drawn in such circuits. Such electrical switching apparatus includes power circuit breakers, network protectors which provide protection, and electrical switches which are used to energize and deenergize parts of the circuit or to transfer between alternative power sources. These devices also include an open spring or springs which rapidly separate the contacts to interrupt current flowing in the power circuit. These open springs are charged during closing by the close spring which, therefore, must store sufficient energy to both overcome the mechanical and magnetic forces for closing as well as charging the open springs. As indicated, either or both of the close spring and open spring can be a single spring or multiple springs and should be considered as either even though the singular is hereafter used for convenience.
A manual handle, and often an electric motor, are provided for charging the close spring. The energy is transmitted to the spring through a cam assembly. In some applications, a ratchet mechanism connects the handle to the cam assembly so that the handle can be reciprocately operated through short repetitive strokes. When the spring is fully charged, the handle is drawn into a stowed position by a return spring. Release of the charged close spring causes the cam assembly to rotate at a very high rate. The rapidly rotating ratchet teeth tend to bounce the handle out of the stowed position which is an undesirable condition.
There is a need, therefore, for improved electrical switching apparatus having a close spring charged by a ratchet mechanism in which the handle is not bounced out of the stowed position when the stored energy in the spring is released during closing.
There is an associated need for such improved electrical apparatus with a disengageable handle which is simple and economical to manufacture and install.